Component Location
P2609 Intake Air Heater System Performance
General Description
The air heater heats air entering into combustion chamber when the engine is cold to make diesel spread and ignite well and functions to reduce soot from exhaust gas when the engine is cold. ETCM controls the drive and drive time of engine pre-heat auxiliary relay to supply power to air heater based on such information as the engine coolant temperature and the ignition key on. And the ETCM displays power supply status of air heater through gage lamp to a driver. Generally the air heater lamp comes off when the ignition turns ON but comes on as much as pre-heat time according to engine temperature.
Using air heater lamp test among actuator tests of scan tool, the operation condition of the air heater lamp can be checked in brief. If the air heater lamp comes on while driving, troubleshooting in pre-heat circuit and relay system should be performed.
DTC Description
The DTC is set when the drive voltage of air heater entering into ETCM differs from air heater control condition of ETCM for more than 32 seconds. In this case ETCM warns a driver by turning a pre-heat lamp on. It is possible to drive but the proper action should be taken through a prompt check.
DTC Detecting Condition
| Item | Detecting Condition | Possible Cause | ||
| DTC Strategy | • Voltage monitoring | • Short to power
• Short to ground • Open in harness |
||
| Enable Conditions |
• Ignition ON or at driving | |||
| Threshold Value |
• Air heater sub relay operate in not operation condition or in reverse |
|||
| Diagnosis Time |
• Above 32 seconds | |||
| Fail Safe | Fuel Cut | No | • Pre-heat lamp ON • Air heater operation stop |
|
| Fuel Limit | No | |||
| MIL | On | |||
Specification
- Air heater sub relay resistance
| (3)-(5) Resistance | (3)-(5):Applying power | (85)-(86):Cut-off power | Relay Type |
| 320 Ω ± 10% (20℃) | (1)-(2) : Continuity | (1)-(2) : Infinite | Normal Open |
| Temperature | Above 0℃ | – 3℃ | – 6℃ | – 9℃ | Below – 12℃ |
| Pre-heater (second) |
0 | 6 | 13 | 21 | 30 |
| Temperature | 5℃ | 0℃ | – 5℃ | – 10℃ | Below – 15℃ |
| Post-heat (second) |
5 | 10 | 20 | 35 | 60 |
| Temperature | 10℃ | 5℃ | – 10℃ | – 15℃ | Below – 20℃ |
| CHOP | 0 | 51 | 151 | 201 | 201 |
Diagnostic Circuit Diagram
Monitor Scantool Data
1. Relay Actuation Test
(1) IG “OFF”, and set the start safety switch ON.
(2) Connect scan tool to the data link connector.
(3) IG “ON”, and set the start safety switch ON. Leave the engine “OFF”
(4) Select the air heater sub-relay from actuation test and press ENTER after matching operation condition.
(5) Is the operation sound of air heater relay from relay box heard normally?
| YES | Go to “Verification of Vehicle Repair” procedure. |
| NO | Go to next step. |
The purpose of this test is sound check of relay. After check, turn the IG key “Off” immediately. If the IG key is in the “On” position unnecessarily for more than I minute, the risk of fire may result.
2. Warning Lamp Operation Inspection
(1) IG “ON”, and set the start safety switch ON. Leave the engine “OFF”.
(2) Confirm that engine pre-heat lamp comes on(normal condition : off) when the engine coolant temperature is above 5℃and the ignition key is in ON position.
(3) Confirm that engine pre-heat lamp comes on and off a short time later when the engine coolant temperature is below -5℃and the ignition key is in ON position. Also confirm that heater relay operates at the same time. In addition to, confirm that heater is operated for about 30 seconds after engine has run.
(4) If the engine pre-heat lamp blinks in any case, there may be pre-heat system problem. Check relevant circuit of the pre-heater system.
3. Is the engine pre-heat lamp turned on normally?
| YES | Go to “Verification of Vehicle Repair” procedure. |
| NO | Go to next step. |
Terminal & Connector Inspection
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
| YES | Repair as necessary and then go to “Verification of Vehicle Repair” procedure. |
| NO | Go to “Signal Circuit Inspection” procedure. |
Signal Circuit Inspection
1.Air Heater Monitoring voltage Inspection
(1) IG “OFF”, and set the start safety switch ON.
(2) Disconnect the ETCM connector.
(3) Leave the air heater harness connecting connector connected and apply battery power to the
terminal 1 of the air heater relay connector.
(4) Measure voltage between terminal 39 of the ETCM connector and chassis ground.
Specification : Approx. 22V
(5) Is the voltage measured within specification?
| YES | Go to “Verification of Vehicle Repair” procedure. |
| NO | Go to “Air Heater Monitoring Short to Power Inspection” procedure. |
2.Air Heater Morning Short to Power Inspection
(1) IG “ON”, and set the start safety switch ON. Leave the engine “OFF”
(2) Disconnect the ETCM connector and air heater relay connector.
(3) Measure voltage between terminal 39 of the ETCM connector and chassis ground.
Specification : Below 0 ~ 0.1V
(4) Is the voltage measured within specification?
| YES | Go to “Verification of Vehicle Repair” procedure. |
| NO | Repair short in circuit and then go to “Verification of Vehicle Repair” procedure. |
Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
- Connect scantool and select “Diagnostic Trouble Codes(DTCs)” mode.
- Using a scantool, clear the DTC.
- Operate the vehicle within DTC enable conditions in General Information.
- Are any DTCs present?
| YES | Go to the applicable DTC procedure. |
| NO | System is performing to specification at this time. |
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